A coordinator completion participant registered on behalf of an interposed WS-BA coordinator in order
to ensure that durable participants in the interposed transaction are completed, closed or cancelled
when requested from the parent transaction.

set the participant manager for this stub. this cannot be supplied to the constructor because it
refers to the engine which drives this participant and the engine can only be created once the
participant has been created. it is needed in order to be able to send a fail upward to the
parent coordinator during complete processing. it is not needed during close or compensate
processing which is ok because we cannot save and restore it anyway.